Detection zoning

[atherton1930]

Guys
What are your thoughts on zoning the following type of building taking in to account search distances.
The building is a production plant 10 floors with a separate enclosed staircase, door to each level.
Each floor is approx 10m x 15m, each floor is steel, grated type, in theory you can see from top to bottom of the building.
The total height of the building is approx 45m.
Staircase obviously one zone but would every floor have to be in its own zone?
Answers on a post card please.

[Monkeh]

I would put each floor on its own zone even just to ease them knowing exactly what detector has operated. It's a strange one because in theory a fire on the ground would be likely to activate devices on higher floors before their own unless the fire is very close to a detector.

Have they thought about beams or ASD which , properly planned and installed, would be more likely to pick up the smoke before it can move up to a higher level?

[atherton1930]

(28-09-2018, 12:25 PM)Monkeh Wrote: I would put each floor on its own zone even just to ease them knowing exactly what detector has operated. It's a strange one because in theory a fire on the ground would be likely to activate devices on higher floors before their own unless the fire is very close to a detector.

Have they thought about beams or ASD which , properly planned and installed, would be more likely to pick up the smoke before it can move up to a higher level?

ASD was my thoughts but would need an ASD for each level,going to be expensive.
Beams will not be practicable because of all the pipes ETC.

[Monkeh]

You could do a multi channel ASD then route the pipework so that it's snaking through each floor with only a few meters between the sampling points. With such a small area you could go total overkill on the sampling points and significantly increase the chance that the fire would be picked up on the floor of origin before the smoke manages to get up to the higher floors.

[atherton1930]

(28-09-2018, 12:53 PM)Monkeh Wrote: You could do a multi channel ASD then route the pipework so that it's snaking through each floor with only a few meters between the sampling points. With such a small area you could go total overkill on the sampling points and significantly increase the chance that the fire would be picked up on the floor of origin before the smoke manages to get up to the higher floors.

Trouble with using say a 4 pipe vesda, 1 pipe for each floor = 4 zones.
If the vesda fails you've lost more than one zone, against BS

[Will Lloyd]

my first question would be is the floor and there-fore the ceiling below perforated?

An explanation and definition of perforated ceilings is given below.
BS 5839-1 recommends that the perforations may be regarded as not obstructing the flow of smoke if:
a) the perforations are uniform, equispaced and make up more than 40% of the surface and
b) a 10mm rod can be passed through the holes and
c) the thickness of the ceiling material is less than 3 x the width of the holes. e.g. for a 10 mm hole the depth of the ceiling thickness should not be more than 30 mm (i.e. the perforations are more than 1/3rd of the ceiling thickness).

If the perforations do not comply with a, b, and c the suspended ceiling should be regarded as solid and detectors will be required on the suspended ceiling as well

if it is perforated ceiling then you can argue that whole thing is one zone if not then i would look into zoning per floor

[atherton1930]

(28-09-2018, 02:07 PM)Will Lloyd Wrote: my first question would be is the floor and there-fore the ceiling below perforated?

An explanation and definition of perforated ceilings is given below.
BS 5839-1 recommends that the perforations may be regarded as not obstructing the flow of smoke if:
a) the perforations are uniform, equispaced and make up more than 40% of the surface and
b) a 10mm rod can be passed through the holes and
c) the thickness of the ceiling material is less than 3 x the width of the holes. e.g. for a 10 mm hole the depth of the ceiling thickness should not be more than 30 mm (i.e. the perforations are more than 1/3rd of the ceiling thickness).

If the perforations do not comply with a, b, and c the suspended ceiling should be regarded as solid and detectors will be required on the suspended ceiling as well

if it is perforated ceiling then you can argue that whole thing is one zone if not then i would look into zoning per floor

Hi Will
Thanks for your input.
Each floor is steel grate flooring, see attachment.
there is only one staircase, this is approx 40m, how would we comply to search distances if all the floors were one zone, staircase its own zone.

[atherton1930]

b) If the total floor area of the building is greater than 300 m2, each zone should be restricted to a
single storey.

[Will Lloyd]

(28-09-2018, 02:21 PM)atherton1930 Wrote: Hi Will
Thanks for your input.
Each floor is steel grate flooring, see attachment.
there is only one staircase, this is approx 40m, how would we comply to search distances if all the floors were one zone, staircase its own zone.

The search distance issue is easy - use an addressable system